List Upload Failed-No Special Characters

I've never had an issue uploading lists until yesterday when two separate lists have failed to upload. Marketo support is saying there are special characters in the list and that @ and . are included as a special character. That makes no sense to me because it's an email marketing platform so an @ in an email address shouldn't block an upload. Plus every list we've ever uploaded has an @ in the email and separates phone numbers with periods.

This is gonna be difficult for us to help with if we can't see the data (which you shouldn't share with us for privacy reasons). Did support specifically say the special characters causing the error were @ and ., and/or that they were in the email address column? You're right, those characters definitely should not cause a list import to fail if contained to the email field, because (obviously) that field does accept those special characters. I'd expect that it's likely that the error was caused by special characters present in another column - one that matched to a field type that doesn't accept them, like an integer field. You might want to do some filtering through the other columns in your spreadsheet to see whether they or other special characters are present in them.